This invention relates generally to a defibrillator with a built-in cardiopulmonary resuscitation (xe2x80x9cCPRxe2x80x9d) prompt system. This invention also relates generally to a defibrillator with a built-in Advanced Cardiac Life Support (xe2x80x9cACLSxe2x80x9d) prompt system. Defibrillators include, manual defibrillators, automatic or semi-automatic external defibrillators (referred to collectively as xe2x80x9cAEDsxe2x80x9d) and defibrillator trainers.
Each day thousands of Americans are victims of cardiac emergencies. Cardiac emergencies typically strike without warning, oftentimes striking people with no history of heart disease. Because of the potentially life threatening nature of cardiac emergencies, it is imperative that victims receive immediate care to prevent permanent damage to the brain or, worse yet, death. Cardiac emergencies include: acute myocardial infarction (commonly referred to as xe2x80x9cheart attacksxe2x80x9d); bradycardia; tachycardia; hypotension and pulmonary edema; ventricular fibrillation (xe2x80x9cVFxe2x80x9d) and ventricular tachycardia (xe2x80x9cVTxe2x80x9d); pulseless electrical activity (xe2x80x9cPEAxe2x80x9d); and asystole. Each cardiac emergency has its own treatment protocol which is determined by the specific symptoms manifested by the victim.
One of the most common cardiac emergencies is sudden cardiac arrest (xe2x80x9cSCAxe2x80x9d). It is estimated that more than 1000 people per day are victims of sudden cardiac arrest in the United States alone.
SCA occurs when the heart stops pumping blood. Usually SCA is due to abnormal electrical activity in the heart, resulting in an abnormal rhythm (arrhythmia). One such abnormal rhythm, VF, is caused by abnormal and very fast electrical activity in the heart. During VF the heart cannot pump blood effectively. VF may be treated by applying an electric shock to the patient""s heart through the use of a defibrillator. The shock clears the heart of the abnormal electrical activity (in a process called xe2x80x9cdefibrillationxe2x80x9d) by depolarizing a critical mass of myocardial cells to allow spontaneous organized myocardial depolarization to resume.
Another abnormal rhythm, treatable by defibrillation, is pulseless VT (xe2x80x9cshockable VTxe2x80x9d). Shockable VT consists of three consecutive QRS complexes originating from the ventricles and recurring at a rapid rate (over 100 beats/minute). More detailed information about electrocardiography and the various types of heart rhythms may be obtained from Wagner xe2x80x9cMarriott""s Practical Electrocardiography,xe2x80x9d 9th Ed. (1994).
It is important to note that not all abnormal heart rhythms are treatable by an electric shock. Several abnormal heart rhythms that are treated as a cardiac emergency require interventions other than defibrillation. However, it is possible for the nature of a cardiac emergency to change during the course of treatment. As a result a cardiac emergency initially having a heart rhythm that is not treatable by defibrillation may become a cardiac emergency where defibrillation is appropriate. Alternatively, a heart rhythm that is treatable by defibrillation may convert to a rhythm that is not treatable by defibrillation during the course of treatment. Accordingly, it is important to adapt the treatment protocol followed in administering care to a victim as the condition of the victim changes.
Even for the abnormal rhythms that are treatable by defibrillation, an electric shock does not always immediately restore a normal heart rhythm. Oftentimes, more than one shock is required.
Because blood may no longer be pumping effectively during a cardiac emergency, the chances of surviving decrease with time after the onset of the emergency. Brain damage can occur after the brain is deprived of oxygen for four to six minutes.
For SCA, if the initial defibrillation shocks are unsuccessful, CPR may be performed in order to keep oxygenated blood flowing to the brain. CPR may also be beneficial after a successful defibrillation shock when the post-shock heart rhythm does not pump a sufficient amount of blood. CPR can also prolong VF, thus maintaining a rhythm that can be analyzed and potentially defibrillated. Effective CPR may make the heart healthier for subsequent defibrillation in patients with VF.
Because quick response to a cardiac arrest is critically important, the American Heart Association (xe2x80x9cAHAxe2x80x9d) developed the xe2x80x9cChain of Survivalxe2x80x9d guidelines, which recite the following steps:
1. Early access to an emergency medical service (xe2x80x9cEMSxe2x80x9d), such as by activating an emergency response system (e.g. calling an ambulance or calling xe2x80x9c911xe2x80x9d);
2. Early CPR initiated by a bystander or other early caregiver to help the patient survive until more advanced care arrives;
3. Early defibrillation; and
4. Early application of Advanced Cardiac Life Support (xe2x80x9cACLSxe2x80x9d), such as airway management, drugs, etc.
The benefits of this approach to survival are discussed in more detail in Cummins, et al. xe2x80x9cImproving Survival from Sudden Cardiac Arrest: the xe2x80x98Chain of Survivalxe2x80x99 Conceptxe2x80x9d Circulation 83:1832-1847 (1991). With the exception of the defibrillation step (#3.), these guidelines are appropriate for treating victims of all cardiac emergencies, not just SCA.
CPR is a combination of artificial respiration (xe2x80x9crescue breathing,xe2x80x9d of xe2x80x9cexpired air resuscitationxe2x80x9d) and artificial circulation (xe2x80x9cexternal cardiac compressionxe2x80x9d or xe2x80x9cexternal chest compressionxe2x80x9d). Typically, if the patient is unconscious and is not breathing, but has a pulse, rescue breathing only is required. Whereas, if the patient is unconscious, is not breathing, and has no pulse, rescue breathing along with external cardiac compression is required.
Rescue breathing is performed by first clearing and opening the air passage. Once the airway is cleared, if the patient is still unable to breathe, the rescuer pinches the nose of the patient and slowly breathes into the mouth of the patient until the patient""s chest rises. Additionally, a barrier mask, bag-valve mask, automatic transport ventilators (xe2x80x9cATVsxe2x80x9d), or oxygen-powered, manually triggered devices may be used by the rescuer during rescue breathing in order to protect the rescuer from direct contact with the patient""s bodily fluids. According to current AHA guidelines, the patient should be ventilated by rescue breathing twice before performing the remaining steps of CPR. Once the patient has been ventilated twice, the patient""s pulse is checked. If a pulse is present, and the patient""s breathing has not resumed on its own, then the rescue breathing procedure should be continued.
Typically with VF, the patient is unconscious, is not breathing and has no pulse. As a result, the patient requires rescue breathing combined with external chest compression.
The rate at which CPR is administered to a patient also depends upon the age of the patient. For example, under the AHA protocol, CPR is performed by administering a repeated sequence of fifteen compressions to two inflations for an initial period of one minute for an adult patient. The pulse and breathing are checked after each one minute interval. Up-to-date CPR protocols recommended by the AHA may be obtained from the AHA internet web site at www.amhrt.org.
The current standards recommended by the AHA for CPR are:
Make sure the scene is safe for help.
Make sure you have the universal precautions: gloves, pocket mask, etc.
Make sure you know how many patients you have.
Determine if they are conscious by tapping and shouting xe2x80x9cAre you okay?xe2x80x9d
If there is no response, have someone call 911.
Position the patient on their back.
Open the airway with a head-tilt, chin-lift or jaw-thrust maneuver.
Look-listen-and-feel for breaths. Check breathing for 5-10 seconds.
If they are not breathing, ventilate twice.
Check pulse for 10 seconds.
If there is no pulse, begin chest compressions and breathing at the following rate for one minute (depending upon the age of the patient):
After one minute, recheck the pulse and repeat the compression/breathing cycle rechecking the pulse at one minute intervals. If there is more than one rescuer, one rescuer should perform the chest compressions and then pause while the other rescuer performs the rescue breathing. Attending to the airway, breathing and circulation, as described above is referred to as xe2x80x9cABCsxe2x80x9d of CPR.
Because of the importance of early CPR in the xe2x80x9cChain of Survivalxe2x80x9d, the AHA and the American Red Cross have promoted training potential rescuers in the basics of CPR for use in medical emergencies for many years. In addition to use in cardiac emergencies, basic CPR is also important in treating patients of a stroke, drowning, auto accidents, suffocation, electrocution, and drug intoxication resulting in cardiac arrest. Although many people have gone through CPR training, most have not maintained their skills, which are quickly forgotten when unused. Even for professionals, it can be difficult to remember protocol changes to a procedure during a given emergency; this is particularly true as the procedures become more complex and as standards change. For some first responders, such as police officers or flight attendants, it can be even more difficult to remember protocol changes because administering CPR or attending to a cardiac emergency is not their primary occupation.
Over the years, many tools have been developed to assist emergency personnel in delivering CPR and recalling the correct sequence of the various steps involved in administering CPR. For example, Parker et al. (U.S. Pat. No. 4,588,383) provides a voice prompting system for a rescuer to follow during a rescue operation. This system is an interactive synthetic speech CPR trainer and prompter. The system has several actuator push buttons for the user to select so that the correct instructions are provided. By providing step-by-step prompting in the protocols and procedures of CPR, this device can guide a rescuer through a CPR protocol.
Another system, developed by Battaglia, is a portable rescue administration aid device (U.S. Pat. No. 5,088,037). This device is designed to be worn on the wrist of a rescuer to assist the rescuer in carrying out the rescue operation. The device provides instructions that can be easily modified and updated, as needed. Additionally, the device can be coupled with other electronic medical storage means for retrieving medical data. The device provides a push-button front-end, into which the rescuer can enter information such as age of the patient, whether the patient is unconscious, whether breathing is present, etc. This device also features an internal timer that is activated when the device is turned-on. Battaglia produces four tones to highlight the steps of the rescue procedure. A recall function is provided that allows the user to reverse the sequence so that the user can recall any message in the instruction sequence and proceed forward from that point.
Swanson et al. (U.S. Pat. No. 5,239,988) developed a CPR aid in the form of a wrist watch. The Swanson device emits audible signals at a rate corresponding to the number of compressions per minute selected. Alternatively, the watch provides a visual signal for timing CPR in noisy areas. Additionally, pulmonary inflation is indicated at appropriate intervals depending upon which compression rate is chosen initially.
Hutchins (U.S. Pat. No. 4,583,524, now Reissue Re. 34,800) developed a self-powered electronic CPR prompting system. The Hutchins system provides a portable device that provides prompts to those previously trained in CPR. Hutchins provides multiple input buttons for the user to enter information regarding the age of the patient, the number of rescuers involved and whether the patient is choking or unconscious. Hutchins enables the user to interactively change the CPR prompts during the course of treatment if the condition of the patient changes.
One drawback of these systems is that they require the rescuer to carry a separate piece of equipment to the emergency setting. This may not always be feasible, depending on the nature of the rescue.
Following the administration of CPR, the availability of ACLS is critical to the victim""s survival, particularly if CPR alone does not resuscitate the victim. ACLS includes, determining the blood pressure of the victim, determining the blood volume of the victim, identifying the type of arrhythmia present and providing treatment which is directed to the specific physiological condition, including defibrillation, administration of drugs, intubation, administering fluids, administering oxygen, and continuing CPR.
Kramer et al. (U.S. Pat. No. 5,405,362) describes an interactive external defibrillator and drug injection system that makes recommendations to the operator for treatment of a patient, based on the input data received. The device described by Kramer et al. also provides a means for vascular drug delivery by intraosseous (xe2x80x9cIOxe2x80x9d) injection.
In addition to widespread training on CPR over the years, there has also been an increase in the number of people who are trained in the proper use of an external defibrillator. The increased number of users increases the likelihood that a trained defibrillator user will be available during an emergency and thus could ultimately reduce the defibrillator deployment time. As the number of people trained in CPR and defibrillator usage increases, however, the frequency with which each rescuer uses the skills developed during training decreases. Depending upon the amount of time since the defibrillator was last used or CPR last performed, the rescuer may be slow to respond as he or she tries to recall all the steps involved in properly deploying a defibrillator and performing CPR. In addition to the protocol for performing CPR, the use of a defibrillator in conjunction with CPR has a separate, albeit related, protocol that must be recalled during an emergency. Such a protocol review, while necessary, delays the speed with which defibrillation and CPR can be performed on the patient. With every second that passes, the likelihood of a patient surviving neurologically intact decreases.
These protocols are further complicated by the need to delivery ACLS for cardiac emergencies that are not treatable by defibrillation. It is also important for an emergency care giver to appreciate that the nature of the emergency can change during treatment which can result in a change in the treatment protocol.
For example, according to the current AHA guidelines, if defibrillation is unsuccessful in converting the heart rhythm after the administration of three consecutive shocks, CPR should be performed for a period of one minute. This xe2x80x9cdefibrillationxe2x80x94CPRxe2x80x9d protocol should be repeated until the patient can be transported to an appropriate medical care facility while a victim has a heart rhythm that is treatable by defibrillation. More detailed information about the xe2x80x9cdefibrillationxe2x80x94CPRxe2x80x9d protocol, including information relating to ACLS, is available in Emergency Cardiac Care Committee, et al., xe2x80x9cIII. Adult Advanced Cardiac Life Supportxe2x80x9d JAMA 268:2172-2183 (1992). This information may be updated from time to time.
In response to the AHA""s xe2x80x98Chain of Survivalxe2x80x99, defibrillator manufacturers have spent many years improving defibrillator technology. The smallest automatic external defibrillator (xe2x80x9cAEDxe2x80x9d) developed to date is the Heartstream, Inc. FORERUNNER(copyright) AED. Once deployed, this small, lightweight AED is capable of analyzing a patient""s electrocardiogram (xe2x80x9cECGxe2x80x9d) to determine whether the heart rhythm can be treated with an electric shock. Once the AED determines that a shock is appropriate, it notifies the rescuer that a shock is advised and instructs the rescuer to deliver a shock by pressing the appropriate button. More detailed information directed to AEDs can be found in Cameron et al. U.S. Pat. No. 5,607,454 and Cole et al. U.S. Pat. No. 5,611,815. The FORERUNNER(copyright) prompts the user to deploy the defibrillator by instructing the user to, for example, xe2x80x9cattach pads.xe2x80x9d
An additional feature of the FORERUNNER(copyright) AED is that a xe2x80x9cpause periodxe2x80x9d can be programmed into the device so that after a predetermined number of shocks the AED ceases analyzing the patient""s heart rhythm in order to allow the user to administer CPR. The pause period lasts for a preprogrammed period of time. Once the pause period has ended, the AED then begins analyzing the heart rhythm to determine whether or not a shock is necessary. The FORERUNNER(copyright) AED also has a voice prompt that says xe2x80x9cif necessary, begin CPR,xe2x80x9d if the patient is not in a shockable rhythm. A pause period can also be programmed after a xe2x80x9cno shock advisedxe2x80x9d decision.
Another AED, the LifePak 100 developed by Physio-Control Corp., prompts the user to, for example, xe2x80x9cperform CPR, deliver 2 breaths and 15 chest compressions.xe2x80x9d These prompts are displayed on an enunciator panel.
Other patient monitoring equipment, such as pulse oximeters (see, e.g. U.S. Pat. Nos. 5,490,523; 5,590,652; 5,588,425; and 5,575,284), pulse detectors (see e.g. U.S. Pat. Nos. 4,519,397; and 4,181,134), blood pressure detectors, or hemodynamic monitors (see, e.g. U.S. Pat. Nos. 5,644,240; and 5,631,552), are known in the art and are not described herein.
Many other defibrillators, including manual defibrillators, and defibrillator trainers have been developed and are known in the art, although not discussed herein.
The disclosures of the patients cited herein are incorporated by reference.
What is needed is a defibrillator or defibrillator trainer that can also instruct a rescuer in the proper protocol for delivering CPR and ACLS to an adult or child victim. Further, what is needed is a defibrillator or defibrillator trainer that can dynamically alter the instructions provided to the rescuer based on changes in the patient""s condition or the level of skill of the operator. Such a device allows the rescuer to treat the patient based on recommendation from the defibrillator using a combination of signs and symptoms as well as heart rate and heart rhythm information, and not treat the device. Finally, what is needed is a defibrillator that allows the rescuer to begin CPR prompts on command.
This invention is directed to a defibrillator system having a defibrillator with an energy source, an electrode interface and an audible sound generator, wherein the electrode interface is in electrical communication with the energy source. The defibrillator may be a manual defibrillator, an AED, or a defibrillator trainer. The defibrillator system also has an instruction generator which communicates with the audible sound generator. The defibrillator system can also have a visual image generator which also communicates with the instruction generator. The instruction generator generates audible prompts or visual images, or a combination of the two. The prompts can be emitted at a predetermined rate or can be synchronized.
This invention is also directed to a defibrillator system having a defibrillator with an energy source, an electrode interface and a visual image generator, wherein the electrode interface is in electrical communication with the energy source. The defibrillator system also has an instruction generator which communicates with the visual image generator. The defibrillator system can also have an audible sound generator which also communicates with the instruction generator. The instruction generator generates audible prompts or visual images, or a combination of the two. The prompts can be emitted at a predetermined rate or can be synchronized.
This invention is also directed to a defibrillator capable of generating audible sound, wherein the defibrillator instructs a rescuer on performing CPR or ACLS. The defibrillator is also capable of generating visual images. The instructions are audible prompts or visual images, or a combination of the two. The prompts can be emitted at a predetermined rate or can be synchronized.
This invention is also directed to a defibrillator capable of generating visual images, wherein the defibrillator instructs a rescuer on performing CPR or ACLS. The defibrillator is also capable of generating audible sound. The instructions can be audible prompts or visual images, or a combination of the two. The prompts can be emitted at a predetermined rate and can be synchronized.
This invention is also directed to a method for administering care which comprises providing CPR or ACLS instructions to a rescuer. The instructions include providing prompts for delivering chest compressions, for delivering artificial breathing, for delivering drugs, for administering oxygen, for intubating, and other instructions for delivering ACLS. The instructions are visual prompts, audible prompts or a combination of the two. The prompts are emitted at a predetermined rate and can be synchronized.